Heidi is a Germanic feminine given name.
It became an internationally popular first name as a direct result of the Swiss children's book, Heidi.
It can sometimes be an affectionate diminutive of the name Adelheid (English: 'Adelaide'), which means "nobility" or, more loosely, "of noble birth".
The name began to be used in the English-speaking world shortly after the 1937 Shirley Temple movie adaptation of the novel.
In German-speaking countries, Heidi is also used as a diminutive for other names, such as Heidrun, Heidelinde, and Heidemarie.